Crane apparatus



Nov. 20, 1962 D. w. SCHAPER CRANE APPARATUS 5 Sheets-Sheet 1 Filed June29, 1961 ATTORNEYS Nov. 20, 1962 w, sc PE 3,064,324

CRANE APPARATUS 5 Sheets-SAaeet 2 Filed June 29, 1961 FIGZ INVENTOR.

. DONALD W. SCHAPER ATTORNEYS Nov. 20, 1962 D. w. SCHAPER CRANEAPPARATUS Filed June 29, 1961 5 Sheets-Sheet 3 INVENTOR.

ATT ORN EYS Nov. 20, 1962 D. w. SCHAPER 3,064,324

CRANE APPARATUS Filed June 29, 1961 5 Sheets-Sheet 4 INVENTOR.

DONALD W. SCHAPER ATTORNEYS United States Patent f q ii.

3,064,324 CRANE APPARATUS Dennis. W. Schaper, Alliance, Ohio, assignorto Elie Morgan Engineering Company, a corporation of Ohio Filed June 29,1961, Ser. No. 121,297 22 Claims. (Cl. 22-95) My invention relates tocrane apparatus and particularly to stripper cranes utilized forseparating metal ingots from the molds in which cast and for handlingthe ingots.

An object of my invention is to facilitate the rotation of the cranebarrel in which a stripper plunger is axially movable for orienting thetongs carried by the barrel without rotating the vertically movableframe on which the barrel is supported.

Another object of my invention is to provide means for rotating thebarrel of a stripper crane to orient the tongs carried by the barrelwithout relative motion between the barrel and a stripping plungerreciprocally movable axially of the barrel.

Another object is the provision for a unique driving arrangement foroperating a stripper plunger, for rotating a barrel in which the plungeris reciprocal and for correlating the operation of the plunger androtation of the barrel to obtain highly useful results.

Another object is the provision of a novel system for orienting thetongs carried by a rotatable barrel of a crane while maintaining thegripping position of the tongs actuated by reciprocation of the plungerrelative to the barrel.

Another object is the provision of improved arrangement for rotating thetong-carrying barrel without rotation of the frame carrying the barrel.

Another object is the provision of a structural arrangement in a craneapparatus which permits the electric motor which rotates thetong-carrying barrel to be fixedly mounted on the vertically movableframe of the crane apparatus and without the motor housing beingrequired to revolve relative to the frame.

Another object is the provision for simplifying and rendering moreefficient the mechanism required for rotating the tong-carrying barrelof a stripper crane to orient the tongs.

Another object is the provision for utilizing the force of a stripperplunger to intensify the gripping action of a pair of tongs movedthrough an initial gripping movement by auxiliary power means.

Another object is the provision for operating a pair of tongs through afirst movement by a motor carried by a stripper crane plunger andthrough a subsequent movement to gripping position by retracting motionof the plunger relative to the tong-carrying barrel.

Another object is the provision for actuating. a first pair of tongs byreciprocal motion of a stripper plunger relative to the barrel in whichthe plunger is axially movable, for actuating a second pair of tongsthrough an initial movement toward gripping position by an auxiliarysource of power carried by the barrel and for actuating the second pairof tongs through a subsequent movement to final gripping position byadditional reciprocal motion of the stripper plunger beyond the point ofmovement required for actuation of the first pair of tongs.

Another object is the provision for obtaining additional and usefulfunctions with a stripper plunger reciprocal relative to the barrel of astripper crane apparatus.

Another object is the combination of the above described features toobtain a novel and highly important combination of structural elementsin a stripper crane.

Another object is the provision of a novel and unique arrangement ofparts and relationship of functions to produce a. new and highly usefulcrane mechanism I edge portion of FIGURE 1,

F a large amount of space on the frame 3,664,324 Patented Nov. 20, 1962"ice giving surprising and advantageous results in operation.

Other objects and a fuller understanding of the invention may be had byreferring to following description and claims, taken in conjunction withthe accompanying drawings, in which:

FIGURE 1 is an elevational view, partially in section, showing the upperportion of my improved apparatus mounted on a vertically movable framesupported by a crane trolley structure;

FIGURE 2 is an elevational view, partially in section, showing the lowerportion of my improved apparatus mounted on such vertically mountedframe. The lower indicated by the letters AA, is to be considered asjoined to the upper edge portion of FIGURE 2, indicated by the lettersAA, so that FIGURES 1 and 2 together, upon such joining of these edgeportions, compose a view of the entire improved apparatus. In FIGURES 1and 2 the upper pair of the crane tongs are in a closed position and thelower pair of the crane tongs are in an open or widespread position;

FIGURE 3 is an elevational view of the lower portion of the apparatusshown in FIGURE 2 and in which the lower pair of tongs has been moved toan initial or preliminary position preceding the full gripping position;

FIGURE 4 is a view similar to that of FIGURE 3 and in which the lowerpair of tongs has been moved through a subsequent range of movement tofull gripping position;

FIGURE 5 is a view of the lower portion of the apparatus shown in FIGURE2 and on the same side thereof and illustrates both the upper and lowertongs in open or widespread positions;

FIGURE 6 is a diagrammatical representation, in simplified form, ofportions only of the electrical circuit arranged for upward movement ofthe electric motor that raises the plunger and of that part of theelectrical circuit of the electric motor powering an auxiliary hydraulicmechanism during one stage only of its operation in a particular rangeof movement.

The stripping cranes to which my invention is directed are used inmetallurgical plants, such as steel plants, for handling of molds inwhich metal ingots have been poured, for stripping or removing theingots from the molds and for gripping and handling the ingots.Stripping cranes of this type are used for removing ingots from both thebig-end-up type of mold and the big-enddown type of mold. It issometimes diflicult to orient the tongs of the crane relative to theload or burden to be gripped and raised, that is, to have the tongs sodirected as to be aligned with opposite, substantially parallel sides ofthe ingot and of the mold.

It has sometimes been attempted to have the whole frame, which is raisedand lowered relative to an overhead trolley, rotate on the axis of theframe for obtaining this result. Other times, to obtain this rotation ofthe crane and orientation of the tongs, it has been necessary to somount the motor which operates the stripping plunger of the crane as torevolve around relative to the vertically movable frame, and this hasrequired a relatively large space for the motor to permit it to revolveand also has required slip rings and electrical brushes to provideelectrical connections with the motor in its different positions ofrevolution. All this has required and special electrical structure formaking and maintaining electrical connections with the motor whichoperates the stripping plunger in those cases wherein the whole housingof the motor is mounted to revolve.

It has also been found that upon rotation of a barrel member of a craneto orient the tongs carried by the barrel member, and which tongs areactuated by recipro- U cal movement of a plunger relative to the barrelmember, that during relative rotation between the rotative shaft and thebarrel there is actuation of the tongs when such actuation is notdesired. For example, when the tongs have gripped and raised an ingot,the tongs should not release and drop the ingot when the barrel memberis being rotated to orient the tOngs about the axis of the barrelmember. It is desired to be able to hold the load carried by the tongsof the crane in full gripping action upon rotation of the barrel memberso as to obtain orientation by rotation of the barrel member. Theovercoming of these and other problems has been accomplished by thepresently described and disclosed invention.

In the composite view made up of the FIGURES l and 2, wherein FIGURE 1represents the upper portion of the crane structure to which myinvention is applied and FIGURE 2 represents the lower portions of thatstructure, a guide frame which is supported by the overhead trolleystructure is denoted by the reference character 11. Slidably mounted inthis guide frame 11 so as to be vertically movable up and down along theguide frame is a movable frame 12. Upon this vertically movable frame 12are mounted and supported the parts of the apparatus embodying myinvention.

A barrel member 13 mounted vertically to the frame 12 is supported on ajournal support 14 riding on a trackw-ay or bushing positionedsubstantially centrally of the frame 12. By this journal mounting 14,the barrel 13 and parts carried thereby may be rotated on the axis ofthe barrel member. As seen in the lower portion of FIG- URE 1 and inFIGURE 2, the barrel member 13 at its lower end portion has an outerwall portion 16 welded thereto so as to leave an annular space betweenthe wall portion 16 and the barrel member 13. There is a bushing orcylindrical bearing 18 around the upper portion of the wall portion 16and another bushing or bearing 19 around a location of the wall portion16 at a lower transverse portion of the frame 12. These bushings orbearings 18 and 19 provide a bearing guidance for the rotation of thebarrel member about its axis in the frame 12.

A plurality of pulleys 15 carried on axles, in turn supported by theframe 12, are reeved with pulleys on a hoist in the overhead trolleystructure, not shown. For purposes of simplicity of illustration, thesteel cables reeved about the pulleys 15 and extending to the pulleys ofthe overhead trolley have not been shown. As is well known in theoperation of such cranes, the vertically movable frame and the partscarried thereon are raised and lowered by the hoist on the trolley incooperation with the cables reeved around the pulleys 15 of the movableframe.

Carried by the frame 12 and mounted concentrically around the wallportion 16 of the barrel member 13 is a casing 17 which is fixed to theframe and is non-rotatively connected to the frame. This casing 17 actsas a shield or protection around the barrel member at its locationintermediate the several pulleys 15.

Disposed axially of the barrel member 13 Within the upper portionthereof is a rotatable shaft 21, the upper end of the shaft 21 extendingupwardly from above the top of the barrel member 13. The lower end 21aof the rotatable shaft 21 is splined so a to provide an elongatednon-circular cross-section at the lower end of the shaft 21.

Keyed to this splined end 21a of the shaft 21 is a screw mechanism 22which is in the form of a sleeve having both internal and externalthreads formed thereon. The external threads on the screw mechanism 22are thre'adably interengaged with the lower threaded end por tion 13a ofthe barrel member 13. The upper end portion of the screw mechanism 22 isso mounted on the splined end 21a of the shaft that relative axialmovement may be had between the screw mechanism 22 and the shaft 21 onrotation of the shaft 21. The internal threads on the screw mechanism 22are threadably engaged with external threads on the threaded end portion23a of a plunger 23 axially aligned with the shaft 21.

The interaction of the screw mechanism 22 with the threaded portion ofthe barrel member 13 and the threaded portion of the plunger 23 is suchthat the mechanism 22 acts as a motion-translating device wherebyrotative movement of the shaft 21 is translated or changed to axialmovement of the plunger 23 along the axis of the barrel member.

The plunger 23 has a nose portion 25 at its lowermost end and securedthereto by means of a threaded head as. The plunger 23 with its noseportion 25v and the head 24 are so connected as. to be movable axiallytogether as a unit and are here referred to jointly as a plunger andmore usually as a stripping plunger.

Welded to the top of the head 24 around the periphery thereof is a guidesleeve 26 of cylindrical shape which is slida'ble in the cylindricalspace provided between the inner wall of the barrel 13 and the outerwall portion 16. This sleeve 26 reciprocates in the annular spaceprovided by the barrel member 13 and the wall portion 16 in such manneras to provide guidance to the reciprocal movement of the plunger, theguide sleeve 26 moving with the plunger as a part of the assemblythereof.

Carried by the upper end portion of the sleeve 2% and extending radiallytherefrom is a key or projection 27. This key 27 is movable in alongitudinal keyway or slot 28 provided in the wall portion 16. Thus theplunger, including the parts 23, 24, 25 and 26, may reciprocate but maynot rotate relative to the barrel member 13.

On a diametrically opposite side of the wall portion 16, there is akeyway or slot 29 which extends upwardly from the lower end of the wallportion 16. An abutting projection or key 24a is carried by the head 24and slides along in the keyway or slot 29 upon reciprocation of the head24.

Carried by the barrel member 13 in such manner as to rotate with thebarrel member are two pairs of tongs, the first or upper pair of tongs32 and the lower or second pair of tongs 37. A first yoke member 31 isso mounted near the lower portion of the barrel member 13 as to beslidably movable up and down relative to the barrel member 13. The firstyoke member 31 has two diagonally disposed or slanted slots 31])positioned on opposite sides of the barrel 13. Slidably mounted on theseslots 31b are cross-pins 33 which are arranged to move up and down inthe slots 31b and as so moving up and down to be moved toward and awayfrom the axis of the barrel member. Thus when the cross-pins 33 aredisposed at the upper ends of the slots 31b, the cross-pins 33 have beenmoved radially inward toward the axis of the barrel member 13. When thecross-pins 33 are in the lower ends of the slots 315, then thecross-pins 33 have been moved radially outward from the axis of thebarrel member 13.

' These cross-pins 33 are mounted to and extend from the upper ends ofthe tongs 32, respectively. Thus the upper ends of the tongs 32 aremoved radially inwardly and outwardly in accordance with the position ofthe crosspins 33 in the slots 31]).

A cross-link 34 carries at its opposite ends pivot pins 35 upon whichare pivotally mounted the tongs 32 at points intermediate theirrespective ends. These pins 35 provide pivot mountings about which thetongs 32 may rock in and out of gripping position. The cross-link 34carrying the pins 35 may move upwardly and downwardly relative to thebarrel member so as to permit the tongs 32 to move upwardly anddownwardly relative to the first yoke member 31 as the pins 33 move inthe slots 31b.

Shown in broken lines directly below the nose portion 25 of the plungerand in a position to be gripped is the top or upper portion of an ingotdenoted by the reference character 36. The ingot 36, of which the topportion is shown, may be protruding upwardly from a mold or it may insome instances have been removed from the mold and be standing aloneready to be gripped, raised and moved to another location.

The second or lower pair of tongs 37 are pivotally carried on pivot pins39 extending through ears 38 provided adjacent the lower end of thebarrel member 13. Because the ears 38 are fixedly secured to the barrelmember 13, they and the lower tongs 37 carried thereby revolve as thebarrel member 13 is rotated. Each tong 37 is of a V-shape inconfiguration. The lower end portion of each tong 37 is denoted by thereference character 37e. The arms of each tong 37 extending upwardlyfrom the lower end portion 372 where they join, are disposed on oppositesides of a tong 32 of the upper set of tongs.

Projecting inwardly toward the axis of the barrel member near thelowermost end of each tong 37 is a point 37a adapted for engaging andpenetrating under pressure an ingot or other burden to be grasped by thetongs 37. Also directed radially inward but at a point somewhat higheron the tongs 37 are projections 37b. These projections 37b are adaptedto engage over the top edge of a mold, such as a big-end-up mold, tohold the mold in a downward position upon extraction of an ingot fromthe mold by the tongs 32.

Also provided on the inner sides of the tongs 37 near the lower endthereof are opposed recesses 37c. These recesses 37c are adapted toreceive and hold the ears or projections extending out from oppositesides of a mold, such as a big-end-down mold, to raise and hold the moldupwardly upon pushing of an ingot from the big-end-down mold by theplunger nose 25.

Angularly extending from the upper ends of the tongs 37 are crank armportions 37d which are integral with the main portion of the tongs 37 sothat revolving of the crank arms 37d about the pivot pins 39 swings thetongs 37 toward and away from the axis of the barrel member 13. Thusupon upward movement of the crank arm portions 37d, the lower ends ofthe tongs 37 are moved radially inward toward the axis of the barrelmember 13, and thus toward any burden, such as the ingot 36 partiallyillustrated in the drawing.

Pivotally connected to the outer or free ends of the crank arm portions37d are pivot pins 40. These pivot pins 40 in turn are pivotallyconnected to the lower ends of vertically disposed rods 41 so thatraising of the rods 41 raises the crank arm portions 37d and moves thelower tongs 37 toward each other, and lowering of the rods 41 converselymoves the lower ends of the tongs 37 away from each other.

The upper ends of the rods 41 extend through tubular bushings secured toand carried by a second yoke member 43 which is so mounted about thebarrel member 13 as to be movable up and down relative to the barrelmember 13. The upper ends of the rods 41 carry disc-type springs '46 andsecuring the springs 46 on the rods 41 are nuts 47. The springs 46 areso biased as to absorb shock and also to urge the rods 41 upwardlyrelative to the bushings 45 on the upper yoke 43. The resiliency of thesprings 46 takes up any lag or delay otherwise occurring in theoperation of the apparatus and slightly delays opening of the tongs 37away from each other which is obtained through downward movement of theupper yoke 43 moving the bushings 45 downwardly.

Extending out from opposite sides and connected to the upper yoke 43 arebrackets or ears 48. Secured to the brackets or ears 48 are the lowerends of piston stems 49 extending upwardly therefrom. These piston stems49 extend into hydraulic cylinders 50 wherein the pistons are reciprocalby admission of hydraulic fluid under pressure to the opposite sides ofthe pistons in the cylinders 50. By operation of appropriate valves in ahydraulic system provided, the pistons in the cylinders 50 arereciprocated so as to move the piston stems upwardly or downwardly inaccordance with the control of the hydraulic system of which thecylinders 50 are a part. The upper ends of the respective cylinders 50are connected and carried by brackets or ears 51 which, in turn, arewelded to a shoulder portion 16a of the outer wall portion 16 carried bythe barrel member. Thus, the yoke member 43 is raised and lowered by thehydraulic piston and cylinder assemblies which are operated andcontrolled by a hydraulic system carried by the barrel.

A supporting bracket 83 is secured to, and supported by, the wallportion 16 of the barrel member 13 at a location adjacent the cylindersStl. Mounted upon this bracket 83 is a pump and valve mechanism denotedby the reference character 76. An electric motor 77 is mounted upon thepump and valve mechanism 76 for operating the pump of the hydraulicsystem. The control of the operation of the motor 77 controls theoperation of the pump and valve mechanism 76 so that the operator by theelectric control of the motor 77 controls the operation of the hydrauliccylinders 50 and hence the raising and lowering of the upper yoke member43.

An arm 82 is secured to the wall portion 16 0f the barrel member 13 soas to extend radially outward from the barrel member to revolve with thebarrel member. This arm 82 carries a plurality of electric brushelements or contact members 78 which are disposed to be in contact withcircular electric contact members or slip rings 84 mounted in fixedposition on a bracket 81 carried by the frame 12. Thus the elements 78are maintained in electrical connection with the slip rings 8%throughout rotation of the barrel member. Slip rings in turn areconnected to the electrical circuit of the crane apparatus so that flowof current through the respective rings 80 and contact elements 78 iscontrolled by the operator of the crane apparatus by manipulation ofswitches in the operators cab of the crane. The cable shown extendingfrom the motor 77 carries wires to the brush elements 78 so that themotor 77 and valve mechanism 76 are operated and controlled through theelectrical circuit and connections maintained through the elements 78and slip rings 80.

Secured to and projecting outwardly of the second yoke member 43 alongthe lower edge portion thereof is a projection or abutting member 44.This projection or abut ting member 44 is in alignment with the topportion of the first yoke member 31. The disposition of the parts issuch that the yoke member 31 may not be moved upwardly beyond theprojection or abutting member 44, but upon reaching the projection 44engages and pushes upwardly upon the projection 44 and hence upon thesecond yoke member 43 carrying the projection 44. Thus the lower portionof the yoke member 43 and the upper portion of the yoke member 31 faceeach other in opposition so that raising of the yoke member 31 to thepoint of contacting the projection 44- and the continued raising of theyoke member 31 tends also to raise or move upwardly the yoke member 43.However, the yoke member 31 may be moved downwardly away from the yokemember 43 so as to disengage and be spaced from the projection 44.

Fixedly mounted upon the top of the frame 12 so as to be carried therebyis a motor 53, which because it powers the actuation of the strippingplunger is sometimes referred to as the stripper motor of the apparatus.The rotor shaft of the motor 53 carries a beveled gear 54, which isenmeshed with a beveled gear 55, which in turn is splined to an innershaft is at right angles to the motor shaft. The arrangement is suchthat the motor drives the vertically disposed inner shaft 5a through theenmeshed beveled gears 54 and 55. The inner shaft 56 is rotatable in abushing 61 carried by the frame 12. Splined to the inner shaft 56 so asto be rotatable therewith is a gear 57. This gear 57 in turn is enmeshedwith an intermediate idler gear 58, which is enmeshed with a gear 5-9splined on the upper end of the shaft 21. The idler gear 53 is rotatablymounted on a shaft 79 supported in bushings carried by the frame. It isthus seen that by the power of the motor 53 and the gear traindescribed, the shaft 21 is rotated in accordance with the direction ofthe 7 rotation of the rotor of the motor 53. The cable shown extendingfrom the motor 53 carries wires connected to the electrical circuit ofthe crane which includes switches in the operators cab of the crane sothat the operator may control the operation of the motor 53 astodirection of rotation and of speed.

Mounted concentrically of the inner shaft 56 and enclosing the lowerportion thereof is a tubular shaft 61. The axes of the inner shaft 56and of the tubular shaft 61 around the inner shaft 56 coincide. Asupporting housing 62 secured to the frame 12 of the crane apparatusencloses and supports through suitable bearings the tubular shaft 61.The arrangement is such that the tubular shaft 61 may rotate on its axiswithin the housing support 62. At the lower end of the concentric innershaft 56 and tubular shaft 61 there is an electromagnetic clutch device64. This clutch device 64 has a clutch part 6-5 carried by a flangedportion 63 which is keyed to the lower end of the tubular shaft 61 so asto rotate therewith. Thus, rotation of the tubular shaft 61 rotates theclutch part 65 of the electromagnetic clutch device 64. Keyed to thelower end of the inner shaft 56 is a clutch part 66 of theelectromagnetic device 64. The clutch part 66 rotates with the innershaft 56. The structure and arrangement of the electromagnetic device 64is such that by a spring bias applied to the parts thereof, the clutchparts 65 and 66 are disengaged when the motor 53 is electrically energled. The electric cable shown extending from the electromagnetic device64 carries wires connected to the electrical circuit of the craneapparatus, of which the controlling switches are in the operators caband the arrangem nt of the circuit is such that when the electric motor53 is electrically energized, the electromagnet device 64 is in adisengaged arrangement so that the inner shaft 56 and the tubular shaft61 are not operatively connected. However, on the de-energization of themotor 53, the flow of electric current is terminated to theelectromagnetic device 64 so as to cause the clutch parts 65 and 66 tobecome engaged by spring action and thus to operatively connect thetubular shaft 61 and the inner shaft 56 so as to rotate together as aunit.

Fixedly mounted upon the frame 12 is another motor 68 which because itis used for turning the barrel member 13 on its axis is often referredto as a turning motor. This motor 68 has shown extending therefrom aneiectric cable carrying wires which are connected to the electricalcircuit of the crane apparatus, including the control switches in theoperators cab. A shaft 69 rotated by the motor 68 extends therefrom andcarries splined on its outer end a worm gear 71 which is enmeshed with apinion gear 72, which in turn is splined to the tubular shaft 61 so asto rotate therewith. Rotation of the shaft 69 by the motor 63 throughthe described gear train rotates the tubular shaft 61 in accordance withthe direction of rotation of the rotor of the motor 68. Embracing theshaft 69 is an electromagnetic brake 79. An electric cable shownextending from the brake 7t? carries wires which are connected to theelectrical circuit of the crane apparatus and to the switches in theoperators cab. The arrangement is such that when the motor 68 isde-energized, then the electromagnetic brake 79 is actuated so as tobrake or stop the rotation of the shaft 69 and hence to brake or stopthe rotation of the tubular shaft 61. Upon the operative connection ofthe tubular shaft 61 and inner shaft 56, the brake 7% upon stoppingrotation of the tubular shaft 61 also stops rotation of the inner shaft56.

Splined to the upper end of the tubular shaft 61 is a gear '73 which inturn is enmeshed with an idler gear 74 carried on a supporting shaft 79.The gear 7 is in turn enmeshed with a gear 75 splined to the upper endof the barrel member 13. Thus rotation of the tubular shaft 61 throughthe described gear train rotates the barrel member 13 in accordance withthe direction and speed of the rotation of the tubular shaft 61.

It is to be noted that the gear ratios of the upper gear train 57, 5Sand 59 are the same as those of the lower gear train made up of gears'73, 7 and 75. Thus the speed and direction of rotation of the shaft 21in the barrel member 13 by the inner shaft 56 are the same as the speedand direction of rotation of the barrel member 13 by the tubular shaft61. Thus, aiso upon rotation of the inner shaft 56 and the outer ortubular shaft 61 together, that is, as a unit, by their operativeconnection through the clutch device 64, the shaft 21 and the barrelmember 13 rotate together and Without any relative motion therebetween.Although the barrel member 13 may rotate with the shaft member 21, thereis no reciprocal movement of the plunger 23 because there is no relativerotation between the shaft 21 and the barrel member 13 when the innershaft 56 and the tubular shaft of are operatively connected to rotatetogether as a unit by the clutch device 64-. The clutch device thus actsas coupling means for operatively connecting the two power-transmittingmeans described.

The upper or first pair of tongs 32, sometimes referred to as theextractor tongs, are actuated by power derived from the reciprocation ofthe stripping plunger 23. As seen in FIGURE 2, the abutting projection24a of the head 24 carried by the stripping plunger extending out intothe keyway 2? extends under and abuts a key portions 31a of the yokemember 3 which key portion 31a also is movable in the keyway 29. Thusraising of the plunger 23 and the head 24 carried thereby raises theyoke member 31 and the tongs 32 and cross-link 34 which are carriedthereby. This raising of the tongs 32 raises a burden, such as the ingot36, engaged by the points 32a embracing or pressing into the sides ofthe ingot. By reason of the inclination of the slots 3112, the raisingof the yoke member tends to force the points 32a on the lower end of thetongs 32 inwardly toward the axis of the plunger and hence into firmgripping engagement with a burden, such as a steel ingot. In the pullingof an ingot from a mold, such as a big-end-up mold, to prevent the moldfrom moving upwardly when the ingot is being extracted therefrom, thelower tongs 37 are moved inwardly so that the projection 37b engagingthe top of the mold holds the mold downwardly while the tongs 32 pullthe ingot upwardly therefrom.

in the ordinary use of the lower tongs 37, for merely bringing them intogether to a position to hold a mold downwardly (for big-end-up molds)or raised (for bigend-down molds), and where no great gripping action isrequired, the tongs 37 are actuated by normal operation of the hydraulicpiston and cylinder assemblies 50. The electric controls of a hydraulicmotor and valve mechanism are so controlled that a normal stroke of thepistons and cylinders 50 are obtained so as to bring the lower ends ofthe tongs 37 downwardly in an initial or normal position, such as in theposition for merely positioning projections 3715 over a mold. The forcerequired for merely manipulating the lower tongs 37 into this initial ornormal position is not great as compared with the force required forlifting an ingot, for example.

My invention includes means for obtaining greater and more intense gripon an object to be lifted, such as a steel ingot, wherein more than thenormal inward movement of the tongs 37 is required. In order to raise asteel ingot, it is necessary to penetrate the ingot by an inward forcingof sharp points, such as the points 37a,

near the lower ends of the tongs 37. As the force exertable by thehydraulic cylinders 51 is not suflicient, I impart additional force forobtaining this greater or more intense gripping action through borrowingpower from the reciprocal plunger 23 upon upward movement thereof.

In the position of both the upper tongs 32 and the lower tongs 37illustrated in FZGURE 5, both sets of tongs are in their widespread orungripping position. As seen in this view, the yoke member 31 is in itslowermost position by reason of the movement of the plunger 9 downwardlyin the barrel member. Also the lower tongs 37 are in their open or mostwidespread position.

FIGURE 2 illustrates the position of the tongs 37 in their widespreadposition ready to grasp or grip an ingot, such as ingot 36. (The tongs32 are shown closed but are not in use.) Upon actuation of the hydraulicpiston piston and cylinder assembly 50, the yoke 43 is raised to raisethe rods 41. The raising of the rods 41 in turn swing the lower tongs 37to the initial or contacting position illustrated in FIGURE 3. Here thepoints 37a have contacted the ingot 36 but enough force has not yet beenapplied to cause penetration of the ingot 36 by the points 37a. Theforce of the hydraulic cylinders has been suflicient to swing the tongs37 to this initial or preliminary position shown in FIGURE 3. It is tobe noted that in this position, the top of the yoke 31 is in line with alocation indicated by a broken line denoted by the letter A in FIGURE 3.The bottom of the projection or abutting member 44 on the yoke 43 is atthe level indicated by a broken line denoted by the letter B in FIGURE3.

In the ordinary operation of the crane apparatus wherein the tongs 32are being utilized for extracting an ingot or for otherwise raising aburden, the electric controls are such that upon the top of the yokemember 31 reaching the level indicated by the broken line A, a limitswitch is engaged and actuated so as to break the circuit to the motor53 and thus to prevent further upward movement of the plunger 23 raisingthe yoke member 31. Thus in such normal operation as in the use of thetongs 32, FIG- URE 3 illustrates the uppermost limit reached by the yokemember 31. Upon reaching this position, the limit switch in theelectrical circuit prevents further upward movement of the yoke member31. To impart additional gripping force to the lower tongs 37, the limitswitch is by-passed by the operator pressing a by-pass circuit switch soas to cause the yoke member 31 to continue to be raised upwardly by theraising of the plunger by continuing the energization of the strippingmotor 53 so that the top of the yoke member 31 engages and abuts thelower surface of the projection 44 at the level indicated by the brokenline marked with letter B in FIG- URE 3.

Also at the level indicated by the broken line marked with the letter Ain FIGURE 3, the electrical circuit energizing the motor '7 7 of thehydraulic system of which the cylinders d are a part, is alsodisconnected by the limit switch. However, this disconnection is alsobypassed by the operator simultaneously pressing a by-pass circuitswitch so as to make ineffective the said limit switch so that thecylinders 59 may continue to raise and pull upwardly on the yoke member43.

Upon the top surface of the yoke member 31 engaging the projection idand pressing upwardly thereon so .as to raise the yoke 43 through theadditional force imparted by the raising of the plunger 23, which liftsthe yoke member 31, a greater and additional force is applied to raisethe rods il. This additional force helps move the tongs 37 toward eachother so as to cause the points 37a to penetrate the ingot asillustrated in FiGURE 4. This additional force applied through borrowingthe force derived from the plunger actuated by the stripping motor 53imparts an intense gripping action on the lower tongs 37 so as to applya greater inward force on the points 37a than could be obtained by thehydraulic piston and cylinder assemblies 50. The by-passing of the limitswitch which ordinarily de-energizes the motor 77 of the hydraulic pumpand valve mechanism allows the hydraulic piston and cylinder assembliesto assist rather than oppose the upward movement of the yoke member 43.Without including this feature of this continued actuation of the motor77 so as to cause the piston and cylinder assemblies 54) to continueupward operation, it is necessary to provide relief or by-pass valvemeans so that upward movement of the pistons in the respective cylinderswould not After the ingot has been id be opposed by the fluid thereinand thus cause rupture or breakage in the hydraulic system.

After the upper yoke member 43 has been raised sufficiently to cause thepenetration of the points 3711 in the ingot by reason of thisintensified or additional gripping action obtainable through theborrowing of power from the upwardly moving plunger, then the top of theyoke member 31 reaches the level or location indicated by the brokenlines marked with the letter C in FIGURE 3. At this level or location, asecond limit switch is engaged and automatically open so as ,totie-energize the motor 53 and prevent additional raising of thestripping plunger and thus prevent breakage of the parts beyond thepoint tolerated by the design and dimensions of the several parts.firmly grasped by this intensified action, such as in the relativeposition of the parts shown in FIGURE 4, the frame 12 may be raised bymeans of the hoisting cables so as to lift and move the ingot to adesired location. Thus, the lower tongs 37 .are utilized for thefunction of gripping and raising objects, such as ingots, and which is afunction in addition to their other uses, previously described.

It is an important feature of the invention that the barrel member andtongs carried thereby may be rotated so that the tongs, such as tongs37, may be oriented, that is, swung around relative to a fixed referencelocation. For example, it may be desired to partially rotate the ingot36 after it has been gripped and raised by the tongs 37. To maintain thefirm and intense grip on the ingot by the tongs 37, it is necessary thatthere be no relative rotative motion between the shaft 21 and the barrelmember 13 If, for example, there were such relative rotation so as tocause the stripping plunger to move downwardly in the barrel member 13,the removal of the intensified grip on the ingot borrowed through theplunger would permit the tongs 37 to loosen their gripon the ingot 36The grip on the ingot would be lost and the ingot would drop from thetongs 37. However, by having the barrel member 13 and the shaft 21rotate together in the same direction and .at the same speed when thebarrel member 13 is rotated on its axis to orient the tongs 37, the firmand intense gripping action of the tongs 37 is uniformly maintained.

To rotate the barrel member 13, the turn motor 68 is energized, thebrake 70 is released, and the electromagnetic clutch device 64 is sooperated as to operatively connect the inner shaft 56 and the tubularshaft 61 to rotate together and thus assure the shaft 21 rotates inunison with the barrel member 13.

There has been illustrated in FIGURE 6, an elementary and diagrammaticshowing of a simple arrangement for the operation of the switch forby-oassing the limit switches. For purposes of simplicity only two powerlines and 86 are illustrated, these lines 85 and 86 being in theelectrical circuit of the apparatus and being connected to a source ofelectrical energy. Connected to and leading from the power line 85 is aconnection 87 which in turn is electrically connected with the motor 53.A line 88 connected to the motor 53 is connected to a limit switch 89.The limit switch 89 is connected by a wire 90 to another limit switch91. This limit switch 91 is electrically connected by a line 92 to theother power line 86.

The limit switch 91 is so located as to be engaged and opened at thelevel or location A indicated in FIGURE 3, upon upward movement of theyoke member 31. The limit switch 89 is located so as to be engaged andopened at the location or level indicated by the letter C in FIG- URE 3,upon upward movement of the yoke member 31. a

A by-pass of the first limit switch 91 is provided by a line 96 toelectrical contact point and by a line 93 to electrical contact point94. The line 96 is electrically connected with the line 92 and line 93is electrically connected with the line 96. The lines 93 and 96 thusbypass the limit switch 9-1 except for the gap between the points 94land 95.

aoeaaaa A line 97 also connected with the power line 85 is connected toa contact point 93. The motor 77 is connected through a line tilt) tothe power line 86 and another wire or line lit/1 connects the motor 77with a contact point 99 spaced from the contact point 98. A switchdevice made up of a push-button 193 biased in open position by a spring104- has spaced double contact members Hi5 and 102. By pressing thebutton 163 inwardly against the bias of the spring 1%, the contactmember 165 electrically connects the contact points 94 and 95 and at thesame time the contact member fill electrically connects the contactpoints 98 and 99. Thus by pressing the switch button 193, the firstlimit switch 9 1 is effectively bypassed so that the motor '53 continuesto be energized until the limit switch 89 is opened by reason of the topof the yoke member 31 reaching the level or location indicated by theline marked with the letter C in FIG- URE 3. Thus between the levels ofthe line B and of the line C, the intensified or greater gripping actionis supplied to the tongs 37 through the borrowing of the additionalpower derived from the raising of the plunger and the power derived fromthe stripping motor 53. This intensified gripping action is considerablygreater than that which could be obtained through the hydraulic pistonand cylinder assemblies which are normally used for raising the yokemember 43 and hence swing the tongs 37 to their initial or preliminaryposition, such as that shown in FlGURE 3.

The present disclosure includes that contained in the appended claims,as well as that of the foregoing description.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by Way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and scope of the invention as hereinafterclaimed.

What is claimed is:

1. In crane apparatus having a vertically movable frame guided invertical non-rotative movement by a guide frame carried by a cranetrolley and raised and lowered by hoisting mechanism carried by thetrolley, the combination of a vertically disposed barrel memberjournaled on said movable frame to rotate on its axis relative to saidmovable frame, a pair of tongs arranged in opposition to each other tograsp an object therebetween upon actuation of the tongs, pivotconnections carried by said barrel member for pivotal support of saidtongs, respectively, the axes of said pivot connections being parallelto each other and disposed in a plane normal to the axis of the barrelmember, a plunger shaft axially disposed in said barrel member andnon-rotatively reciprocal therein to extend from said barrel member,tong-actuating means operatively interconnecting said plunger shaft andsaid tongs to actuate said tongs upon reciprocal movement of the plungershaft relative to sad barrel member, screw mechanism in said barrel meaber and threadably engaging said barrel member and said plunger shaftto reciprocate the plunger shaft upon rotation of the screw mechanismrelative to said barrel member, an electric motor mounted in fixedposition on said movable frame movable therewith, driving connectionmeans operatively connecting said electric motor and said screwmechanism for turning the same by the said electric motor to reciprocatesaid plunger shaft, powerdriven means carried by the movable frame andoperatively connected to said barrel member for rotating said barrelmember on its axis and revolving said tongs about said axis to orientthe said tongs, and coupling means for operatively coupling said drivingconnection means and said power-driven means to cause rotation of thescrew mechanism in accordance with the rotation of the barrel memberupon rotation of said barrel member by said power-driven means o preventrelative rotative movement of screw mechanism relative to the barrelmembe and to maintain the longitudinal position of the plunger shaftrelative to the barrel member, said driving connection means and saidpower-driven means between said coupling means and said screw mechanismand between said. coupling means and said barrel member beingproportioned to impart equal rotative speed to said screw mechanism andsaid barrel member upon the coupling of said driving connection meansand said powerdriven means.

2. The combination defined in claim 1 and in which said power-drivenmeans for rotating the barrel member includes another and separatelycontrolled electric motor carried by said movable frame.

3. The combination defined in claim 1 and in which said power-drivenmeans includes a brake for locking said power-driven means againstmovement to prevent rotation of the member upon independent operation ofthe drivin connection means to rotate the screw mechanism relative tosaid bar-rel member fo reciprocation of the plunger shaft.

4. in crane apparatus having a stripper plunger reciprocal in avertically disposed barrel membe by rotation of a screw mechanismpositioned in the barrel member concentrically therewith, a drivingshaft extending axially of the barrel member and operatively connectedin the barrel member to the screw mechanism to rotate the same, saidbarrel member being rotatively mounted on a vertically movable andnon-rotatable frame to rotate on its axis relative to the said frame andto be raised and lowered with the frame relative to a supportingtrolley, said barrel member carrying tongs journaled on pivots disposedin planes normal to the axis of the barrel member and having jawsmovable toward and away from the axis of the barrel member uponreciprocal movement of the stripper plunger relative to the barrelmember, the improvement comprising the combination of, an electric motorcarried by said frame, power-transmitting means carried by said frameand operatively connecting said electric motor and said driving shaft torotate the driving shaft and said screw mechanism by the said electricmotor, said power-transmitting means including a first rotating memberrotatable on an axis parallel to and spaced from the axis of saiddriving shaft, power-driven mean carried by the said frame andoperatively connected to said barrel member for revolving said barrelmember and the said tongs about the axis of said barrel member to orientthe said tongs, said power-driven means including a second rotatingmember disposed concentrically with said first rotating member androtatable on said axis parallel to the axis of the driving shaft, clutchmeans for operatively interengaging said first and second rotatingmembers, said power-transmitting means and said power-driven means uponbeing interengaged by said clutch means being proportioned to rotatesaid driving shaft and said barrel member together at equal rotativespeeds.

5. The improvement defined in claim 4 and in which said power-driven mans includes another and separately controlled electric motor carried bysaid frame.

6. The improvement defined in claim 4 and in which said power-drivenmeans includes a brake for locking said power-driven means againstmovement to prevent rotation of the barrel member upon independentoperation of the power-transmitting means to rotate the driving shaftand screw mechanism relative to said barrel member for reciprocation ofthe stripper plunger.

7. In a stripper crane, the combination of a barrel member carried by aframe vertically movable relative to a crane trolley, tongs carried bythe barrel member, a plunger mounted in said barrel member toreciprocate therein, said plunger being adapted to push an ingot from amold upon protrusion of the plunger from said barrel member and adaptedto actuate said tongs into ingot gripping action upon retracting motionrelative to said barrel member, a shaft axially extending into saidbarrel member at the upper portion thereof, a screw mechanism in saidbarrel member threadably interengaged with said shaft and said plungerwhereby rotation of said shaft relative to said barrel member causesreciprocation of said plunger relative to said barrel member, anelectric motor mounted on said frame, a first gear concentricallymounted on said shaft and keyed thereto, a second gear concentricallymounted on said barrel member and keyed thereto, a first driven geartrain operatively connecting said electric motor and said first gear forrotating said first gear and shaft upon operation of said first drivinggear train, a second driving gear train operatively connected to saidsecond gear for rotating said second gear and barrel member uponoperation of the second driving gear train, and selectively actuatablecoupling means for coupling said first and second driving gear trains inunison, said first and second driving gear trains and said first andsecond gears, respectively, being in such ratio that the said shaft andsaid barrel member are rotated at the same speed upon the coupling ofsaid first and second driving gear trains to prevent relative rotationbetween the shaft and barrel member.

8. The combination defined in claim 7 and in which a second electricmotor is operatively connected to said second driving gear train forpowering said second driving gear train independently of said firstdriving gear train.

9. The combination defined in claim 7 and including braking meanscarried by said frame and operatively connected to said second drivinggear train, said braking means being arranged for automaticallypreventing the rotation of said second gear and barrel member upondiscontinuance of operation of said second driving gear train.

10. The combination of an upright barrel member, a plunger axiallymounted therein adjacent a lower end of the barrel member, a shaftaxially mounted therein adjacent an upper end of the barrel member, amotiontranslating member in said barrel member and interengaging saidplunger and shaft to translate rotative movement of the shaft relativeto the barrel member to reciprocal movement of the plunger relative tothe barrel member, crane tongs carried by the barrel member revolvableabout the axis of the barrel member upon rotation of the barrel member,means operatively interengaging said plunger and tongs for actuation ofthe tongs by reciprocal movement of the plunger, a firstpower-transmitting mechanism operatively connected to said shaft forrotating the same relative to the barrel member, a secondpowertransmitting mechanism operatively connected to said barrel memberfor rotating the same and revolving the tongs about the axis of thebarrel member, said first and second power-transmitting mechanismshaving concent rically disposed portions, and selectively actuatableclutch means adapted to connect operatively said concentrically disposedportions to rotate said shaft and barrel member simultaneously, saidfirst and second power-transmitting means upon being connected beingarranged to rotate the shaft and barrel member at uniform speed anddirection to assure maintenance of the relative positions of saidplunger and barrel member upon rotation of the barrel member.

11. The combination defined in claim 10 and including a first electricmotor operatively connected to said first power-transmitting mechanismfor delivering power thereto and an independently controlled secondelectric motor operatively connected to said second power-transmittingmechanism for delivering power thereto.

12. The combination defined in claim 19 and including a brakeoperatively connected to said second powertransmitting mechanism tobrake the same and prevent rotation of the barrel member upontermination of trans- 1% mission of power through the secondpower-transmitting mechanism to the barrel member.

13. In stripper crane apparatus having a supporting frame verticallymovable relative to an overhead crane structure, a vertically disposedbarrel member journalled on said frame for rotation about its axis, astripping plunger axially mounted in said barrel member and reciprocalrelative to said barrel member, a shaft axially mounted in said barrelmember and axially aligned with said stripping plunger, screw mechanismmounted in said barrel member and threadably engaged to said shaft andsaid plunger to translate rotative motion of the shaft relative to thebarrel member to reciprocal motion of the plunger relative to the barrelmember, the combina tion of a first electric motor carried by saidframe, a spindle member rotated by said electric motor, a tubular memberconcentrically mounted on said spindle member, electro-magneticactuatable clutch mechanism positioned to operatively couple saidspindle member and tubular member, said electro-magnetic clutchmechanism being controlled by supply of electric current to said firstelectric motor to actuate the electro-magnetic clutch mechanism so as todisconnect the spindle member and tubular member upon electricalenergization of said first electric motor, a second electric motorcarried by said frame operatively connected to said tubular member torotate the same upon electrical energization of said second electricmotor, an electro-magnctic brake mechanism operatively connected to saidtubular member, said electro-magnetic brake mechanism being controlledby supply of electric current to said second electric motor to actuatethe electro-magnetic brake mechanism to break the rotation of thetubular member upon electrical de-energization of said second electricmotor, first connecting means operatively connecting said spindle memberand said shaft for rotating the shaft, second connecting meansoperatively connecting said barrel member for rotating the barrelmember, the rotation of the tubular member by the second electric motorduring coupling of the tubular member and spindle member by theelectro-magnetic clutch mechanism causing the barrel member and shaft torotate in unison, the said first and second connecting means being soproportioned and arranged that upon such rotation in unison the shaftand barrel rotate at the same speed and direction.

14. Apparatus for rotating the tong-carrying barrel of a stripper cranewithout reciprocal movement of a tongactuating stripper plunger relativeto the barrel, the plunger being carried by and reciprocal relative tothe barrel by rotation of a screw mechanism relative to the barrel, saidbarrel and plunger being in axial alignment and operativelyinterconnected by said screw mechanism, said screw mechanism being atleast partially within said barrel, comprising first driving means forrotating the screw mechanism, second driving means for rotating thebarrel member, selectively actuatable coupling means for coupling saidfirst driving means and second driving means to rotate said screwmechanism and barrel member at such speeds and direction as to preventreciprocal movement of the plunger relative to the barrel, and brakemeans operatively connected to said second driving means for brakingrotation of the barrel member by the second 7 driving means uponuncoupling of the first and second driving means and independentrotating of the screw mechanism by the first driving means.

15. In stripper crane apparatus, the combination of a barrel member, astripping plunger reciprocal in said barrel member, first power meansfor raising said plunger relative to said barrel member, a first set oftongs pivotably carried by said barrel member, a first yoke membercarried by said barrel member to be moved therealong and operativelyconnected to said first set of tongs to actuate the same to grippingposition upon upward movement of the first yoke member relative to saidbarrel member, said plunger and said first yoke member having firstabutting portions disposed in oppositon to each other to interengageupon upward movement of said plunger to a first limit point for raisingsaid first yoke member by the upward movement of the plunger beyond saidfirst limit point, a second set of tongs pivotally carried said barrelmember, a second yoke member carried by said barrel member to be movedtherealong and operatively connected to said second set of tongs toactuate the same in a motion toward gripping position upon upwardmovement of the second yoke member relative to the barrel member, secondpower means carried by said barrel member and operatively connected tosaid second yoke member for raising said second yoke member a firstdistance relative to said barrel member for actuating said second set oftongs through an initial stage of said motion toward gripping position,said first yoke member and second yoke member having second abuttingportions disposed in oppositon to each other to interengage upon theupward movement of the first yoke member to a second limit point forraising said second yoke member a second distance additional to saidfirst distance by the upward movement of the first yoke member beyondsaid second limit point, said upward movement of the second yoke memberthrough said second distance actuating said second set of tongs througha subsequent stage of said motion toward gripping position.

16. In stripper crane apparatus having a barrel member, a strippingplunger axially mounted to said barrel member and reciprocally movablethereto, first power means operatively connected through the barrelmember to the plunger for upwardly moving the plunger relative to thebarrel member, a first set of tongs carried by the barrel member andactuatable to gripping position by upward movement through a firstdistance of a first yoke member raised by said plunger, the upwardmovement of the first yoke member through said first distance by saidplunger being terminable by limit means controlling said first powermeans to discontinue upward movement of the plunger by said first powermeans, a second set of tongs carried by the barrel member and actuatableto an initial gripping position by upward movement an initial distanceof a second yoke member raised by second power means carried by thebarrel member, the improvement of first abutting means carried by thefirst yoke member, second abutting means carried by the second yokemember and disposed to face said first abutting means in opposingrelationship, said first and second abutting means being spaced fromeach other during movement of the second yoke member through saidinitial distance, and means for opposing said limit means to permit saidfirst yoke member to move upwardly beyond said first distance and tocause said first and second abutting means to interengage, additionalupward movement of the second yoke member by the first yoke memberthrough said interengaged first and second abutting means actuating saidsecond pair of tongs to a subsequent gripping position.

17. In crane apparatus having a first pair of tongs carried by avertically disposed barrel member, a second pair of tongs carried by thebarrel member, and a plunger reciprocally movable axially of said barrelmember, the combination of first means for actuating the first pair oftongs by an upward movement of said plunger through an initial range ofupward movement, second means independent of said first means forinitially actuating said second pair of tongs to a first grippingcondition of intensity, and third means operable subsequent to saidinitial actuation of the second pair of tongs by another upward movementof the plunger through a second range of upward movement following saidinitial range of upward movement to actuate the second pair of tongs toa second gripping condition of intensity greater than said firstgripping condition.

18. In stripper crane apparatus having a frame vertically movablerelative to a supporting guide structure, a

barrel member journaled on said frame to rotate on its axis, a plungeraxially mounted in said barrel member and reciprocal relative thereto,first rotative drive means carried by the frame, motiorntranslatingmeans carried by said barrel member and operatively connecting saidfirst rotative drive means and said plunger for moving the plungeraxially of the barrel member by rotation of said first rotative drivemeans, second rotative drive means carried by said frame operativelyconnected to said barrel member for rotating the barrel member, couplingmeans for selectively coupling said first and second rotative drivemeans to rotate said motion-translating means and barrel togetherwithout relative motion therebetween to hold the plunger against axialmovement relative to the barrel member upon rotation of the barrelmember, a first pair of tongs pivotally carried by the barrel member tomove in gripping action toward the axis of the barrel member, a secondpair of tongs pivotally carried by the barrel member to move in grippingaction toward the axis of the barrel member, rotation of said barrelmember providing orientation of said pairs of tongs carried thereby,first means driven by upward movement of said plunger to a referencepoint for actuating said first pair of tongs to move the same intogripping action by a first upward movement of said plunger, power meanscarried by said barrel member and operatively connected to said secondpair of tongs for moving said second pair of tongs through an initialstep of movement in gripping action, and second means driven by upwardmovement of the plunger beyond said reference point for actuating saidsecond pair of tongs to move the same through a step of movement ingripping action subsequent to said initial step of movement, saidinitial step being greater in extent of the movement of the second pairof tongs and said subsequent step being greater in the force applied tothe second pair of tongs for gripping action.

19. In a stripper crane, the combination of first rotative driving meansfor obtaining reciprocal movement of a stripping plunger along the axisof a rotative barrel member carrying said stripping plunger andoperatively connected thereto, second rotative driving means forrotating the barrel member for orienting a first pair of tongs and asecond pair of tongs pivotally carried by the barrel member to revolvethe tongs around the axis of the barrel member, coupling means forselectively coupling said first and second driving means for operatingthe same together at speeds to avoid reciprocal movement of the plungerrelative to the barrel member during rotation of the barrel member,first interengaging means operatively connecting the plunger and thesaid first pair of tongs for actuating said first pair of tongs byupward movement of the plunger through a first range of movement of theplunger, independent power means carried by the barrel memberoperatively connected to said second pair of tongs for moving the secondpair of tongs an initial distance toward gripping position, and secondinterengaging means operatively connecting the plunger, through saidfirst interengaging means, and the said second pair of tongs for movingthe second pair of tongs a succeeding distance to final grippingposition upon upward movement of the plunger through a subsequent rangeof movement of the plunger.

20. The combination claimed in claim 19 and in which said independentpower means includes hydraulic piston and cylinder means, and in whichthe initial distance the second pair of tongs is moved by theindependent power means is greater than said succeeding distance and inwhich the gripping force applied to the second pair of tongs by saidsecond interengaging means is greater than the gripping force applied tothe second pair of tongs by the independent power means during movementthrough said initial distance.

21. In stripper crane apparatus, the combination of a barrel member, aplunger carried by and reciprocal relative to said barrel member, firstpower means for raising said plunger relative to said barrel member, afirst yoke member carried by said barrel member to be moved therealong,said plunger and said first yoke member having first abutting portionsdisposed in opposition to each other to interengage upon upward movementof said plunger to a first limit point for raising said first yokemember by the upward movement of the plunger beyond said first limitpoint, a pair of tongs pivotally carried by said barrel member, a secondyoke member carried by said barrel member to be moved therealong andoperatively connected to said pair of tongs to actuate the same in amotion toward gripping position upon upward movement of the second yokemember relative to the barrel member, second power means carried by thebarrel member and operatively connected to said second yoke member forraising said second yoke member a first distance relative to said barrelmember for actuating said pair of tongs through an initial stage of saidmotion toward gripping position, said first yoke member and said secondyoke member having second abutting portions disposed in opposition toeach other to interengage upon the upward movement of the first yokemember to a second limit point for raising said second yoke member asecond distance additional to said first distance by the upward movementof the first yoke member beyond said second limit point, said upwardmovement of the second yoke member through said second distanceactuating said pair of tongs through a subsequent stage of said motiontoward gripping position.

22. In a stripper crane apparatus having a barrel memher, a strippingplunger axially mounted to said barrel member and reciprocally movablerelative thereto, first power means operatively connected through thebarrel 118 member to the plunger for upwardly moving the plungerrelative to the barrel member, a first yoke member rais- -able by saidplunger by upward movement of the plunger,

the upward movement of the first yoke member through a first distance bysaid plunger being terminable by limit means controlling said firstpower means to discontinue upward movement of the plunger by said firstpower means, a pair of tongs carried by the barrel member and actuatableto an initial gripping position by upward movement an initial distanceof a second yoke member raised by second power means carried by thebarrel member, the improvement of first abutting means carried by thefirst yoke member, second abutting means carried by the second yokemember and disposed to face said first abutting means in opposingrelationship, said first and second abutting means being spaced fromeach other during movement of the second yoke member through saidinitial distance, and means for opposing said limit means to permit saidfirst yoke member to move upwardly beyond said first distance and tocause said first and second abutting means to interengage, additionalupward movement of the second yoke member by the first yoke memberthrough said interengaged first and second abutting means actuating saidpair of tongs to a subsequent gripping position.

References Cited in the file of this patent UNITED STATES PATENTS2,302,631 Hively Nov. 17, 1942 2,009,219 Harry Nov. 21, 1961 FOREIGNPATENTS 1,092,773 France Nov. 10, 1954

